Re: next-20241031: kernel/time/clockevents.c:455 clockevents_register_device

[Frederic Weisbecker <frederic@kernel.org>]

On Thu, Oct 31, 2024 at 10:42:45AM +0100, Thomas Gleixner wrote:
> On Thu, Oct 31 2024 at 14:10, Naresh Kamboju wrote:
> > The QEMU-ARM64 boot has failed with the Linux next-20241031 tag.
> > The boot log shows warnings at clockevents_register_device and followed
> > by rcu_preempt detected stalls.
> >
> > However, the system did not proceed far enough to reach the login prompt.
> > The fvp-aemva, Qemu-arm64, Qemu-armv7 and Qemu-riscv64 boot failed.
> >
> > Please find the incomplete boot log links below for your reference.
> > The Qemu version is 9.0.2.
> > <4>[ 0.220657] WARNING: CPU: 1 PID: 0 at kernel/time/clockevents.c:455
> > clockevents_register_device (kernel/time/clockevents.c:455
> > <4>[ 0.225218] clockevents_register_device+0x170/0x188 P
> > <4>[ 0.225367] clockevents_config_and_register+0x34/0x50 L
> > <4>[ 0.225487] clockevents_config_and_register (kernel/time/clockevents.c:523)
> > <4>[ 0.225553] arch_timer_starting_cpu
> > (drivers/clocksource/arm_arch_timer.c:1034)
> > <4>[ 0.225602] cpuhp_invoke_callback (kernel/cpu.c:194)
> > <4>[ 0.225649] __cpuhp_invoke_callback_range (kernel/cpu.c:965)
> > <4>[ 0.225691] notify_cpu_starting (kernel/cpu.c:1604)
> 
> That's obvious what happens here. notify_cpu_starting() is invoked
> before the CPU is marked online, which triggers the new check in
> clockevents_register_device().
> 
> I removed the warning and force pushed the fixed up branch, so that
> should be gone by tomorrow.

Ah, phew!

Thanks.

> 
> Thanks,
> 
>         tglx
>